Organisms, Organs, Cells and Organelles: in vivo and in vitro Experimental Systems

In germinating oilseeds peroxisomal fatty acid poxidation is responsible for the mobilization of storage lipids. This pathway also occurs in other tissues where it has a variety of additional physiological functions. The central enzymatic steps of peroxisomal p-oxidation are performed by acylCoA oxidase (ACOX), the multifunctional protein (MFP) and 3-ketoacyl-CoA thiolase (thiolase). In order to investigate the function and regulation of /?-oxidation in plants it is first necessary to identify and characterize genes encoding the relevant enzymes in a single model species. Recently we and others have reported on the cloning and characterization of genes encoding four ACOXs and a thiolase from the oilseed Arabidopsis thafiana. Here we identify a gene encoding an Arabidopsis MFP (AtMFP2) that is induced transiently during germination. The pattern of AtMFP2 expression closely reflects changes in the activities of 2-trans-enoyl-CoA hydratase and L-3-hydroxyacyl-CoA dehydrogenase. Similar patterns of expression have previously been reported for ACOX and thiolase genes. We conclude that genes encoding the three main proteins responsible for /?-oxidation are co-ordinately expressed during